The proposed study will evaluate the feasibility and effectiveness of process change techniques for hazard prevention. Process changes include chemical substitution, process modification, and substitute technologies that intervene in the industrial process itself to eliminate or reduce hazards. The effectiveness of process change interventions will be evaluated by assessment of the technical, occupational health and safety, environment, organizational and financial aspects of process changes to eliminate methylene chloride from industrial operations. The investigators will examine these issues both retrospectively and prospectively in selected Massachusetts companies. Evaluation tools will include industrial hygiene and ergonomic measurement techniques, pollution prevention options evaluation software, and interviews of key personnel at each field site. Results will include case study reports describing the benefits and unintended consequences of process change techniques, motivations for and barriers to change, cost-effectiveness analysis and specific guidance on promoting occupational health and safety via process change interventions.